He had first tried to murder Robert Seddon, 68, and mother Patricia, 65, by driving into a canal with them strapped in the back seats in a faked road accident. Seddon then "played the hero" in the aftermath, after aborting the murder plan when bystanders went to their aid in the submerged car.

But after that plan failed, four months later he blasted the couple to death with a sawn-off shotgun at their suburban home in Sale, Greater Manchester.

His parents had made him sole beneficiary of their £230,000 estate in their will - and paid with their lives. His parents had already gifted him £40,000 in cash and bought his home in Seaham, Co Durham, to keep a roof over his head.

The father-of-three, from Benevente Street in Seaham, County Durham, was convicted of two counts of attempted murder on March 20 last year and two counts of murder on July 4, after a five-week trial at Manchester Crown Court.

The victims' family shouted "Yes!" and burst into tears, hugging each other in the public gallery. Seddon now faces four mandatory life sentences.

Mr Justice Hamblen will pass sentence on Thursday and decide how long Seddon should serve behind bars before he can apply for parole - or order that he serves a "whole life" term and is never released.

Seddon had lived the high life in the past, posing in his Bentley Turbo, jetting around the world and staying at the Waldorf Astoria in New York on one trip. The money came from a scam and he was jailed for fraud.

Peter Wright QC, prosecuting, described him as the ultimate "ungrateful son" who had an "insatiable thirst for cash".